1. Field of the Invention
The present invention relates to a solid-state image sensor, and more particularly to a solid-state image sensor which is capable of performing exposure control in accordance with the quantity of light incident on image sensor cells while detecting it during exposure.
2. Description of the Prior Art
In conventional types of cameras employing a silver salt photographic material it is impossible to control exposure in accordance with the quantity of light incident on a photosensitive material. Accordingly, it is general practice to perform exposure by changing at least one of the lens aperture (the intensity of light incident on the photosensitive material) and the shutter speed (the exposure time of the photosensitive material) by a signal based on the quantity of light incident on a sensor provided separately of the photosensitive material. The same is true of known solid-state image sensors employing optoelectro transducers such as CCDs, BBDs and so forth. That is, the prior art solid-state image sensors are incapable of exposure control such as control of the lens aperture and the exposure time in accordance with the quantity of light incident on their optoelectro transducer unit, and hence they have the defect of difficulty in accurate exposure control.